Question 4
Hexagon $AB^{\prime} CA^{\prime} BC^{\prime}$ has $ABC$ equilateral, its angles $A^{\prime} BC^{\prime},C^{\prime} AB^{\prime},B^{\prime} CA^{\prime}$ greater than $120^\circ$, and $AB^{\prime}=AC^{\prime}$, $BA^{\prime}=BC^{\prime}$, $CA^{\prime}=CB^{\prime}$. Prove that $AB^{\prime},BC^{\prime},CA^{\prime}$ are the side lengths of a triangle.